1. Field of the invention:
The present invention relates to a cone crusher by which raw material such as ore is crushed between a gyrating mantle and a bowl liner mounted above the mantle.
2. Prior art:
In the cone crusher of the noted type, because raw material is fed and crushed between the mantle and the bowl liner, surfaces of both the mantle and the bowl liner are worn away and recede as a result of repetition of such a crushing operation, also the crushing space formed between the mantle and the bowl liner is gradually enlarged eventually resulting in lowering of crushing performance. It is, therefore, essential to adjust the crushing space by changing the position of either the mantle or the bowl liner with the progress of wear and tear.
In this positional adjustment, there are various factors to be considered which should be chosen between the mantle and the bowl liner. Both a mantle adjustment type crusher and a bowl liner adjustment type crusher have been put into practical use and improved in their positional adjustment so far. The two types of crushers are now compared from the viewpoint of their crushing performance after being subject to the positional adjustment with reference to FIGS. 5 (a) and (b).
The crushing performance of cone crusher can be comparatively expressed by "throw" on the condition that the configuration of the crushing chamber, number of gyrations and materials to be crushed are equal. In the drawings, the center line H of the mantle 44 and the center line J of the main shaft intersect each other at the point O at the top of the crusher, and the space between the line H and the line J becomes larger in the lower part.
FIGS. 5 (a) and (b) show a cone crusher in which the mantle 44 is moved upward to reduce (or adjust) the space between the mantle 44 and the bowl liner 31 in the event that the mantle 44 has been worn away and its surface receded. Referring to FIGS. 5 (a) and (b), the point G (the lowest point of the crushing chamber showing the maximum throw) is shifted upward to the point G1, whereby the throw is reduced by L1, which means lowering of the crushing performance by as much. On the other hand, when adjusting the space by moving the worn bowl liner 31 downward, FIGS. 5 (c) and (d) the point G is shifted downward to the point G2, and the throw is increased by L2, which means improvement of the crushing performance by as much.
Accordingly, as far as the crushing performance is concerned, it may be said that the bowl liner adjustment type crusher is superior to the mantle adjustment type one. This bowl liner adjustment type crusher has been further classified into various subtypes each having been improved in their own way.
FIG. 6 shows a cone crusher most popularly used, in which a cylindrical member 3a, to which the bowl liner 31a is fixed to be mounted above an mantle 44a, is engaged with the upper frame 2a by a bolt (not shown). Thus, the bowl liner 31a can be moved up and down by turning the bolt thereby also turning the bowl liner, whereby the space between the bowl liner 31a and the mantle 44a is adjusted.
In the event of receiving any abnormal shock (due to excessive feed of raw material, for example) at the crushing chamber of the crusher of this type, the shock may be absorbed at four corners of the crusher where upper frame 2a and lower frame 1a are secured to each other with a plurality of spring jacks 101.
Japanese Patent Application Publication (examined) No. Sho 39-6929 discloses as shown in FIGS. 7 (a) and (b) a crusher in which a cylindrical member 3b, to which the bowl liner 31b is fixed, is slidably inserted in a cap frame 2b of the main frame, and the cylindrical member 3b is supported telescopically with a plurality of fluid cylinders 102.
This prior art is intended to smoothly shocks, and to perform positional adjustment of the bowl liner 31b in the vertical direction by converting the rotation of a fluid motor 103 into vertical movement of a setting adjust bar 104, thereby "vertically" and "the" --sliding-- vertically the cylindrical member 3b to draw up the bowl liner 31b.
Japanese Patent Application Publication (examined) No. Sho 61-26424 also employs a method of moving a bowl liner 31c upward, as shown in FIGS. 8 and in which a rod 105 is disposed between an upper frame 2c and a lower frame 1c so that the cylindrical member 3c may slide vertically within the upper frame 2c by telescopically moving the rod with a cylinder 106.
Among the foregoing prior art, the most popular cone crusher shown in FIG. 6 has a disadvantage of requiring too much time and labor for providing taps on the inner and outer peripheries of large and heavy components (i.e., upper frame 2a and cylindrical member 3a). Moreover, because the crushing load is absorbed by means of springs, the upper frame may be violently moved up and down in the event of excessive load eventually resulting in early wear and tear of the portion of the upper frame engagedly inserted into the lower frame 1a. Since the shocks due to fluctuation of the load are abosorbed by the plurality of spring jacks, adjustment exactly following vertical movements of the cylindrical member is very difficult. Besides, it is not easy for the bowl liner 31a to be turned in a required circumferential direction to be reset to an adjusted position because it is quite rare that a partially worn part of the bowl liner is coincident with turning of the bolts for vertical movement of the bowl liner when the bowl liner is worn away.
When employing the cone crushers shown in FIGS. 7 and 8 in which absorption of overload and positional adjustment of the bowl liner are both carried out by the plurality of liquid cylinders, there is a disadvantage that it is difficult to keep a balance with respect to the entire circumference resulting in application of partial load if an insufficient number of such cylinders are disposed. On the contrary, if a large number of such cylinders are disposed, there is another disadvantage that it is difficult to cause every cylinder to perform a harmonious and uniform function eventually requiring troublesome fine adjustment.